This invention relates to monitoring of an individual's presence and movement. “Presence” as used herein refers to an individual's location, especially with reference to a particular room of a building (e.g., the presence of a person within a specific location in a kitchen or a living room, such as standing in a corner or seated at a table). “Movement” as used herein refers to an individual's movement, especially with reference to leg, arm, or head movement (e.g., the movement of a person as the person walks from one point in a room to another, or the shifting of a person's body or head posture while otherwise standing or sitting still).
Monitoring an individual's presence and movement is useful in a wide variety of applications. Security cameras are commonplace in government and business facilities, and use thereof is increasing in private residences. GPS (global positioning satellite) sensors worn by individuals suffering from dementia detect “wandering” behavior in those individuals and alert caregivers. Baby monitors with video cameras allow parents to keep a vigilant eye on their children.
Monitoring for presence and movement comes with an important trade-off: the more precise and convenient the monitoring, the more invasive it is of an individuals' privacy. Security cameras—which are both precise and convenient—record a person's appearance and visage, and using modern facial recognition algorithms, can even reveal a person's identity. Such cameras, which are precise and convenient, are highly invasive of privacy. On the other hand, worn GPS sensors are less invasive, but are less precise and less convenient.
Because of this trade-off, any type of monitoring that requires precision and convenience, coupled with privacy, cannot currently be readily satisfied. An important example is the monitoring of older individuals in their own home. Specifically, it is desirable to monitor the presence and movement of an older individual who lives alone, in order to reassure friends and family that the individual is doing well, is able to move around, is not sick, has not fallen into a hypoglycemic coma, has not fallen down, etc.
However, older individuals actively (and appropriately) are opposed to placing video cameras or similar devices into their homes that will show what they are wearing, what they look like, what they are reading, what they are watching on TV, etc. There is an important unmet need to monitor older individuals in their own homes while respecting and protecting their privacy.
Known methods of monitoring presence and movement suffer from one or more of the following disadvantages:                Known methods may generate visual data that show a person's face or body, or show what the person is wearing, or show what the person is reading or watching, thereby invading privacy;        Known methods may be susceptible to “reverse engineering” whereby visual images of the individual may be reconstructed from underlying data, even if the known methods attempt to obfuscate or to hide such images;        Known methods may require that specific devices, such as GPS devices, be physically worn by an individual;        Known methods may be imprecise and/or inconvenient;        Known methods may be unable to distinguish between multiple persons at the same time, or between persons and animals.        Known methods may require a lighted environment to work, and thus fail to work in the dark.        